Devices that guide cardiopulmonary resuscitation (CPR) during a cardiac arrest rescue have been in existence for a number of years. The QCPR meter, manufactured by Laerdal Medical AS, for example, is a puck-like device which is placed on the patient's chest, over which manual CPR compressions are applied. FIG. 1 illustrates an exemplary CPR meter 20 as applied by a rescuer 12 to an adult cardiac arrest patient 14. Additionally shown is an automatic external defibrillator (AED) 10, which senses the patient's cardiac ECG signals via electrodes 16 placed across the patient's chest.
FIG. 1 shows a typical application of the CPR meter 20 over the patient's sternum. Once placed, the rescuer 12 places his hands over the CPR meter and applies CPR compressions to the patient's chest. The CPR meter 20 senses the force and displacement of the compressions via an internal force sensor and accelerometer and then processes the force and displacement signals with an internal processor. The CPR meter 20 then outputs audible and/or visual instructions for guiding the proper rate and depth of CPR compressions during the rescue. Although FIG. 1 shows that the CPR meter 20 is connected to the AED 10 via a cable, the CPR meter may also be a stand-alone device.
The proper rate and depth of CPR compressions differs between adults and infants. Current CPR Guidelines recommend a 1½″ to 2″ compression displacement for adults at a rate of about 100 compressions per minute. CPR guidelines for infants are less aggressive at about ⅓ to ½ of the depth of chest at a rate of about 60 compressions per minute. It can be seen that unless the CPR guidance device can discriminate between adult and infant patients, there is a risk that a rescuer will be erroneously guided by the CPR device to apply adult therapy to an infant, and thus potentially injure the infant with inappropriately deep and rapid compressions.
FIG. 2 shows a CPR meter 20 that has been applied to an infant patient 18. Because current AED practice is to apply defibrillation electrodes in the anterior-posterior position, it is seen that the CPR meter 20 is placed over the electrode. Use of the CPR meter 20 in this situation can potentially damage the electrode or the CPR meter during rescue. For these reasons, no prior art CPR meter is indicated for use on infant cardiac arrest patients.
Prior art CPR meters rely on user training to ensure that adult CPR protocols are not mistakenly applied to infants. For example, users of the QCPR meter are trained never to apply the meter to an infant. The labeling also warns against such application. Users of AEDs to which the CPR meter is connected may allow use of the AED on infants by inserting a key which changes the AED operation to an infant mode. Neither solution completely eliminates the risk of improper CPR meter use on an infant. What is needed is an improved method of ensuring that a CPR meter is not used on an infant patient.